- ID:
- ivo://CDS.VizieR/J/A+A/516/A42
- Title:
- Spectral lines of BK Peg and BW Aqr
- Short Name:
- J/A+A/516/A42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Double-lined, detached eclipsing binaries are our main source for accurate stellar masses and radii. In this paper we focus on the 1.15-1.70M_{sun}_ interval where convective core overshoot is gradually ramped up in theoretical evolutionary models. We aim to determine absolute dimensions and abundances for the F-type detached eclipsing binary BK Peg, and to perform a detailed comparison with results from recent stellar evolutionary models, including a sample of previously studied systems with accurate parameters.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/373/687
- Title:
- Spectra of 5 faint cataclysmic variables
- Short Name:
- J/MNRAS/373/687
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present medium-resolution VLT/FORS2 spectroscopy of six cataclysmic variables (CVs) discovered by the Sloan Digital Sky Survey (SDSS). We determine orbital periods for SDSS J023322.61+005059.5 (96.08+/-0.09min), SDSS J091127.36+084140.7 (295.74+/-0.22min), SDSS J103533.02+055158.3 (82.10+/-0.09min) and SDSS J121607.03+052013.9 (most likely 98.82+/-0.16min, but the one-day aliases at 92 and 107min are also possible) using radial velocities measured from their H{alpha} and H{beta} emission lines. Three of the four orbital periods measured here are close to the observed 75-80min minimum period for CVs, indicating that the properties of the population of these objects discovered by the SDSS are substantially different to those of the CVs found by other means. Additional photometry of SDSS J023322.61+005059.5 reveals a periodicity of approximately 60min which we interpret as the spin period of the white dwarf, suggesting that this system is an intermediate polar with a low accretion rate. SDSS J103533.02+055158.3 has a period right at the observed minimum value, a spectrum dominated by the cool white dwarf primary star and exhibits deep eclipses, so is an excellent candidate for an accurate determination of the parameters of the system. The spectroscopic orbit of SDSS J121607.03+052013.9 has a velocity amplitude of only 13.8+/-1.6km/s, implying that this system has an extreme mass ratio. From several physical constraints we find that this object must contain either a high-mass white dwarf or a brown-dwarf-mass secondary component or both.
- ID:
- ivo://CDS.VizieR/J/A+A/557/A79
- Title:
- Spectra of KIC10661783
- Short Name:
- J/A+A/557/A79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- KIC 10661783 is an eclipsing binary that shows delta Sct-like oscillations. More than 60 pulsation frequencies have been detected in its light curve as observed by the Kepler satellite. We want to determine the fundamental stellar and system parameters of the eclipsing binary as a precondition for asteroseismic modelling of the pulsating component and to establish whether the star is a semi-detached Algol-type system. We measured the radial velocities of both components from new high-resolution spectra using TODCOR and compute the orbit using PHOEBE. We used the KOREL program to decompose the observed spectra into its components, and analysed the decomposed spectra to determine the atmospheric parameters. For this, we developed a new computer program for the normalisation of the KOREL output spectra. Fundamental stellar parameters are determined by combining the spectroscopic results with those from the analysis of the Kepler light curve. We obtain Teff, logg, vsini, and the absolute masses and radii of the components, together with their flux ratio and separation. Whereas the secondary star rotates synchronously with the orbital motion, the primary star rotates subsynchronously by a factor of 0.75. The newly determined mass ratio of 0.0911 is higher than previously thought and means a detached configuration is required to fit the light curve. With its low orbital period and very low mass ratio, the system shows characteristics of the R CMa-type stars but differs from this group by being detached. Its current state is assumed to be that of a detached post-Algol binary system with a pulsating primary component.
- ID:
- ivo://CDS.VizieR/J/AJ/144/63
- Title:
- Spectroscopic and photometric observations of V335 Ser
- Short Name:
- J/AJ/144/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- V335 Ser is now known to be an eccentric double-lined A1+A3 binary star with fairly deep (0.5mag) partial eclipses. Previous studies of the system are improved with 7456 differential photometric observations from the URSA WebScope and 5666 from the NFO WebScope, and 67 high-resolution spectroscopic observations from the Tennessee State University 2m automatic spectroscopic telescope. From dates of minima, the apsidal period is about 880 years. Accurate (better than 2%) masses and radii are determined from analysis of the two new light curves and the radial velocity curve. Theoretical models match the absolute properties of the stars at an age of about 380Myr, though the age agreement for the two components is poor. Tidal theory correctly confirms that the orbit should still be eccentric, but we find that standard tidal theory is unable to match the observed asynchronous rotation rates of the components' surface layers.
- ID:
- ivo://CDS.VizieR/J/A+A/473/523
- Title:
- Spectroscopic monitoring of 3 neutron stars
- Short Name:
- J/A+A/473/523
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a spectroscopic monitoring campaign of the OB-star companions to the eclipsing X-ray pulsars SMC X-1, LMC X-4 and Cen X-3. High-resolution optical spectra obtained with UVES on the ESO Very Large Telescope are used to determine the radial-velocity orbit of the OB (super)giants with high precision. The excellent quality of the spectra provides the opportunity to measure the radial-velocity curve based on individual lines, and to study the effect of possible distortions of the line profiles due to e.g. X-ray heating on the derived radial-velocity amplitude.
- ID:
- ivo://CDS.VizieR/J/AJ/147/148
- Title:
- Spectroscopy and photometry of AP And
- Short Name:
- J/AJ/147/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- AP And is a well-detached F5 eclipsing binary star for which only a very limited amount of information was available before this publication. We have obtained very extensive measurements of the light curve (19097 differential V magnitude observations) and a radial velocity curve (83 spectroscopic observations) which allow us to fit orbits and determine the absolute properties of the components very accurately: masses of 1.277+/-0.004 and 1.251+/-0.004M_{sun}_, radii of 1.233+/-0.006 and 1.1953+/-0.005R_{sun}_, and temperatures of 6565+/-150K and 6495+/-150K. The distance to the system is about 400+/-30pc. Comparison with the theoretical properties of the stellar evolutionary models of the Yonsei-Yale series of Yi et al. shows good agreement between the observations and the theory at an age of about 500 Myr and a slightly sub-solar metallicity.
- ID:
- ivo://CDS.VizieR/J/AJ/147/1
- Title:
- Spectroscopy and photometry of HP Aur
- Short Name:
- J/AJ/147/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New photometric, spectroscopic, and eclipse timing observations of the eclipsing binary star HP Aur allow for very accurate orbital determinations, even in the presence of a third body and transient starspot activity. The eclipsing binary masses are determined to an accuracy of +/-0.4% and the radii to +/-0.6%. The masses are 0.9543+/-0.0041 and 0.8094+/-0.0036 solar masses, and the radii are 1.0278+/-0.0042 and 0.7758+/-0.0034 solar radii, respectively. The orbital period in the outer orbit is accurately determined for the first time: 4.332+/-0.011yr. A comparison with current theories of stellar evolution shows that the components' absolute properties can be well-matched by the current models at an age of about 7 billion years.
- ID:
- ivo://CDS.VizieR/J/AJ/149/34
- Title:
- Spectroscopy and photometry of IM Per
- Short Name:
- J/AJ/149/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IM Per is a detached A7 eccentric eclipsing binary star. We have obtained extensive measurements of the light curve (28225 differential magnitude observations) and radial velocity curve (81 spectroscopic observations) which allow us to fit orbits and determine the absolute properties of the components very accurately: masses of 1.7831+/-0.0094 and 1.7741+/-0.0097 solar masses, and radii of 2.409+/-0.018 and 2.366+/-0.017 solar radii. The orbital period is 2.25422694(15) days and the eccentricity is 0.0473(26). A faint third component was detected in the analysis of the light curves, and also directly observed in the spectra. The observed rate of apsidal motion is consistent with theory (U=151.4+/-8.4year). We determine a distance to the system of 566+/-46pc.
- ID:
- ivo://CDS.VizieR/J/AJ/148/71
- Title:
- Spectroscopy and photometry of V501 Her
- Short Name:
- J/AJ/148/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- V501 Her is a well detached G3 eclipsing binary star with a period of 8.597687days for which we have determined very accurate light and radial-velocity curves using robotic telescopes. Results of these data indicate that the component stars have masses of 1.269+/-0.004 and 1.211+/-0.003 solar masses, radii of 2.001+/-0.003 and 1.511+/-0.003 solar radii, and temperatures of 5683+/-100 K and 5720+/-100K, respectively. Comparison with the Yonsei-Yale series of evolutionary models results in good agreement at an age of about 5.1Gyr for a somewhat metal-rich composition. Those models indicate that the more massive, larger, slightly cooler star is just beyond core hydrogen exhaustion while the less massive, smaller, slightly hotter star has not quite reached core hydrogen exhaustion. The orbit is not yet circularized, and the components are rotating at or near their pseudosynchronous velocities. The distance to the system is 420+/-30pc.
- ID:
- ivo://CDS.VizieR/J/AJ/159/24
- Title:
- Spectroscopy & Kepler data of the EB star V404 Lyr
- Short Name:
- J/AJ/159/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first high-resolution spectra for the eclipsing binary V404Lyr showing {gamma}Dor pulsations, which we use to study its absolute properties. By fitting models to the disentangling spectrum of the primary star, we found that it has an effective temperature of T_eff,1_=7330{+/-}150K and a rotational velocity of v_1_sini=148{+/-}18km/s. The simultaneous analysis of our double-lined radial velocities and the pulsation-subtracted Kepler data gives us accurate stellar and system parameters of V404Lyr. The masses, radii, and luminosities are M1=2.17{+/-}0.06M_{sun}_, R1=1.91{+/-}0.02R_{sun}_, and L1=9.4{+/-}0.8L_{sun}_ for the primary, and M2=1.42{+/-}0.04M_{sun}_, R2=1.79{+/-}0.02R_{sun}_, and L2=2.9{+/-}0.2L_{sun}_ for the secondary. The tertiary component orbiting the eclipsing pair has a mass of M_3b_=0.71{+/-}0.15M_{sun}_ in an orbit of P_3b_=642{+/-}3d, e_3b_=0.21{+/-}0.04, and a_3b_=509{+/-}2R_{sun}_. The third light of l_3_=4.1{+/-}0.2% could be partly attributable to the K-type circumbinary object. By applying a multiple frequency analysis to the eclipse-subtracted light residuals, we detected 45 frequencies with signal-to-noise amplitude ratios larger than 4.0. Identified as independent pulsation modes, seven frequencies (f_1_-f_6_, f_9_), their new pulsation constants, and the location in the Hertzsprung-Russell diagram indicate that the pulsating primary is a {gamma}Dor-type variable star.
